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SubjectRe: [PATCH] 2.6.0-test4: Trivial /sys/power/state patch, sleep status report
Date
Bernd Petrovitsch wrote:
> On Tue, 2003-08-26 at 00:25, P. Christeas wrote:
> > Just found out that by 'echo sth_wrong > /sys/power/state' the kernel
> > would oops in a fatal way (no clean exit from there).
> > The oops suggested that the code would enter an invalid fn.
> >
> > You may apply the included patch to solve the bug. IMHO doing a clean
> > exit is much preferrable than having BUG() there.
>
> > diff -Bbur /diskb/users/panos/linux-off/kernel/power/main.c
> > /usr/src/linux/kernel/power/main.c ---
> > /diskb/users/panos/linux-off/kernel/power/main.c 2003-08-23
> > 12:13:17.000000000 +0300 +++
> > /usr/src/linux/kernel/power/main.c 2003-08-26 00:59:34.000000000 +0300 @@
> > -500,7 +514,7 @@
> > if (s->name && !strcmp(buf,s->name))
> > break;
> > }
> > - if (s)
> > + if ( (s) && (state < PM_SUSPEND_MAX) )
> > error = enter_state(state);
> > else
> > error = -EINVAL;
>
> What do you think about the attached patch to solve the bug and remove a
> warning?
>
> Bernd

Already tried that. If you look more closely, the s will receive the state
*before* the name *in it* is strcmp()'ed. This means it won't be NULL anyway.
> if (s->name && !strcmp(buf,s->name))
> break;

I also thought of checking "( (s) && (s->name !=NULL) )" , but IMHO the
'state' check is cleaner (no dereference).


--- linux-2.6.0-test4/kernel/power/main.c Sat Aug 23 01:53:13 2003
+++ linux-2.6.0-test4-patched/kernel/power/main.c Mon Aug 25 21:16:50
2003
@@ -492,7 +492,7 @@
static ssize_t state_store(struct subsystem * subsys, const char * buf,
size_t n)
{
u32 state;
- struct pm_state * s;
+ struct pm_state * s = NULL;
int error;

for (state = 0; state < PM_SUSPEND_MAX; state++) {

-
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